Moog Focal 903, User Manual

Page: 72 / 96

903-0628-00 Rev. 1 Model 903-HD User's Guide – FMB-X-2.5
Focal Technologies Corp. Page 6-8
The Model 903 diagnostics software is also helpful during bench testing. Presence of data errors on the
program’s display screen may be used instead of the “Link” LEDs to determine the receiver thresholds. This
provides a more accurate power budget, since as received power drops, errors occur in the data frames
before synchronization is lost. By default the FMB-X-2.5 cards are calibrated at the factory when a new 903
system is shipped and no calibration should be required, but if a calibration is deemed necessary then please
consult the 903-0622-00 diagnostic manual.
When the Model 903 is initially turned on or when the optical connection is initially made, the uplink and
downlink transmitters send synchronization frames to ensure reliable transmission before sending actual data
frames. In the event that either the uplink or downlink is lost or exhibits significant frame errors, the
multiplexer will revert both links to synchronization frames until reliable transmission is re-established. If, for
example, the fiber jumper between the two modules is momentarily disconnected, the uplink and downlink
transmitters will send synchronization frames until the connection is remade. When sufficient optical power is
present, synchronization (lock) occurs within 3 milliseconds. Both data and synchronization frames are
transmitted with a nominal 50% duty cycle allowing accurate and consistent measurements of optical power
regardless of which frame type is active.
6.5 Maintenance
The unit requires no routine maintenance or calibration for the specified performance. Maintenance of the
units is limited to cleaning the various components using the methods described below.
The outer surfaces of the modules can be cleaned using a damp cloth. Do not use solvents or damage to
painted surfaces may result.
Dust or dirt on the cards can be blown off using compressed air. If severe contamination of the cards should
occur, they can be removed and cleaned using distilled water. Cards must be thoroughly dried before
reapplying power.
In order to maintain optical performance, it is necessary to ensure the fiber optic connectors are kept clean.
Use a suitable solvent, such as isopropyl alcohol, and a lint free cloth to carefully wipe any dirt off the face of
the ceramic ferrules prior to making a connection. Always replace dust caps on the Model 903 fiber optic
bushings when removing connectors. If bushings are left open, they should be cleared of dust with
compressed air prior to connection.
Fiber connectors should be inspected prior to installation with an optical fiber scope to ensure there is no
contamination or damage to the ferrule or fiber. Contaminated connectors account for the vast majority of
optical link problems, hence it's critical to ensure they are clean prior to mating them. Refer to section 5.3 of
this document for more information about fiber handling.
NEVER look into the end of a fiber when it is plugged
into a transceiver or active fiber, especially when
using a magnifying instrument, such as a fiber
microscope.